How do I calculate what percentage X is of Y?

Divide X by Y and multiply by 100. For example, to find what percentage 25 is of 200: (25 ÷ 200) × 100 = 12.5%.

How do I calculate a percentage increase?

Percentage increase = ((new value - old value) ÷ old value) × 100. For example, from 80 to 100: ((100 - 80) ÷ 80) × 100 = 25% increase.

How do I add a percentage to a number?

Multiply the number by (1 + percentage/100). For example, add 15% to 200: 200 × 1.15 = 230.

Percentage Calculator

Calculate percentages in multiple ways: what percent is X of Y, percentage change, add or subtract a percentage from a number.

Percentage (%)Number

The percentage calculator finds a percentage of a number, the percentage change, and increases or decreases. Percent means hundredth (% = /100).

How the calculator works and what it’s for▾

The most common calculations

Percentage of a number: X% of Y = Y × X/100. E.g. 20% of 150 = 30.

What percent X is of Y = X / Y × 100. Percentage change = (new − old) / old × 100.

Percent vs percentage point

These are often confused. If a rate rises from 5% to 7%, that’s a 2 percentage-point rise but a 40% relative increase. Use the right term especially with interest rates and vote shares.

Example

A product costs €80 with a 25% discount: discount €20, final price €60. If a price rises from €60 to €75, the increase is 25%.

Tips

Successive discounts don’t add up: 30% + 20% is not 50% but 44% (the second applies to the already discounted price). An increase followed by the same-percent decrease does not return to the original price.

🔄 Reviewed June 2026